Aspergillus fumigatus is a serious medical menace and ranks as the most severe filamentous mold causing human disease with 60% overall reported fatality. The increasing population of susceptible immunocompromised individuals coupled with the rising incidence of antifungal resistant fungal isolates underscore the need for new diagnostic and therapeutic modalities. Identification of fungal and host molecules suitable for diagnostic or therapy development is the major goal of this proposal. Compiling data from genomic studies of A. fumigatus/host interactions, we have uncovered 30 A. fumigatus transcription factors (TFs) critical for the two fungal morphologies important in disease development: spores required for initial infection and hyphae, the form of the fungus growing invasively in vivo. Aim 1 thus focuses on identification of spore armaments and fungal/host crosstalk in initial host encounters mediated by spore specific TFs. Aim 2 characterizes the fungal TFs and host molecules enabling invasive hyphal growth in vivo. Simultaneously to Aims 1 and 2, Aim 3 will develop state-of-the-art microfluidic platforms that allow, for the first time, screening of 1000s of A. fumigatus mutants for invasive growth properties and host activation of A. fumigatus virulence proteins. This latter aim is critical for the Aspergillus research community due to the relative ease of generating A. fumigatus mutants and the pipeline availability of a complete A. fumigatus genome knockout library (10,000 genes); screening of this many mutants renders animal studies a major roadblock in assessment of A. fumigatus virulence factors. Indeed, the study of Aspergillus host interactions has been limited by the lack of available robust platforms that (i) enable visualization of intimate fungal/host interactions, (ii) allow for rapid assessment of virulence traits or (iii) evaluate the role of fungal and host signaling molecules that are difficult to obtain in large enough quantities for macrostudies. Aim 3 will provide these platforms to help the research community meet the needs of the Aspergillus genomic era.